The present invention relates to a control device for an ultrasonic motor for controlling to drive the ultrasonic motor to a target position according to a driving signal having a resonance frequency of the ultrasonic motor.
Conventionally known is a control device for controlling to continuously drive an ultrasonic motor to a target position by continuously applying a driving signal to the ultrasonic motor. According to such a control device, the ultrasonic motor is driven to the target position at a constant speed by the driving signal having a resonance frequency of the ultrasonic motor. However, in driving the ultrasonic motor to the target position by the conventional control device, the ultrasonic motor is rapidly stopped at the target position. As a result, a shock is generated upon rapid stoppage of the ultrasonic motor, and a positioning accuracy is reduced.